Exemplary embodiments pertain to the art of electrical machines and, more particularly, to a method and apparatus for loading stator windings into a stator core of an electrical machine.
Many electrical machines, such as alternating current electric generators, include a stator assembly and a rotor assembly arranged in a housing. The stator assembly is mounted to the housing and includes a generally cylindrical stator core provided with a plurality of slots. Conductors or stator windings are fitted into the plurality of slots in a predetermined pattern. The stator windings are formed of slot segments that are located in select ones of the plurality of slots to form a multi-phase winding pattern and end loop segments that connect between adjacent slot segments. The rotor assembly includes a rotor attached to a shaft that is rotatably mounted to the housing coaxially with the stator core. The rotor is rotated within the stator core to develop an electrical current.
Inserting the stator windings into the plurality of slots is a complex task. In some arrangements, a winding needle lays a wire into one of the plurality of slots, advances and lays the wire into another of the plurality of slots. This process continues until the stator core is wound and each of the plurality of slots is filled. At this point, the wire is cut to form the multiple phases. In other arrangements, a wire is preformed with slot segments interconnected by end loops. The slot segments are spaced so as to be inserted into select ones of the plurality of slots in a predetermined pattern. The wire is then loaded directly into the stator core with the slot segments being inserted into the select ones of the plurality of slots. Once the wire is loaded into the stator core, another wire is prepared and loaded in a similar manner. This process continues, each wire being inserted individually into the stator core, until the multi-phase pattern is complete. In still other arrangements, the wire is formed, transferred to a receiver having a plurality of slots, and loaded into corresponding slots provided in a transfer tool. With this arrangement, each wire that makes up one of the multiple-phases is formed, individually transferred to the slots in the receiver, and individually transferred from the slots in the receiver to the slots in the transfer tool. At this point, the transfer tool is inserted into the stator core and the wires are loaded into the plurality of slots.